Inkjet Head Layering Order for Photocurable Ink Curing

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Solution Overview

Problem

Inkjet recording apparatuses face issues with film strength of layered photocurable inks due to uneven light distribution, where the ink layer with the largest light blocking effect is often positioned on top, blocking light from reaching deeper layers and preventing proper curing.

Innovation Solution

The apparatus is configured to first jet the photocurable ink with the largest light blocking effect onto the recording medium, ensuring it is positioned in the deepest layer, allowing light to pass through and reach all layers for effective curing, and optionally adjusts the light source or pigment absorption to optimize curing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If the photocurable color ink with high photocurability is jetted first, then bleeding is prevented, but the film strength becomes lower due to insufficient light penetration to deeper layers

Engineering Contradiction:

Improvebleeding preventionVSAvoidfilm strength

Core Design Contradiction:

Stability of the object's compositionVSStrength

Solution Approach 1:

The patent inverts the conventional jetting order by jetting inks with larger light blocking effects first (creating deeper layers) and inks with smaller light blocking effects later (creating top layers). This ensures light penetrates through top layers to cure deeper layers effectively, while still preventing bleeding through proper layer sequencing. The jetting order is determined by light blocking effect magnitude rather than photocurability alone.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent assigns different jetting positions (top layer vs. deep layer) based on the local optical properties (light blocking effect) of each ink type. Inks with large light blocking effects are positioned in deeper layers where they can be properly cured by light penetration, while inks with small light blocking effects are positioned in top layers. This localized positioning optimizes both curing and bleeding prevention.

Inventive Principle:

Principle #3Local quality

2Stability of the object's composition

If the ink layer with large light blocking effect is positioned on top, then bleeding is prevented, but light penetration to deeper layers is blocked

Engineering Contradiction:

Improvelayer stabilityVSAvoidlight penetration efficiency

Core Design Contradiction:

Stability of the object's compositionVSUse of energy by moving object

Solution Approach 1:

The patent inverts the conventional layer arrangement by positioning inks with large light blocking effects in deeper layers and inks with small light blocking effects in top layers. This inverted structure allows light to penetrate efficiently from the top through layers with small blocking effects to reach and cure the deeper layers containing inks with large blocking effects, thereby optimizing light energy utilization.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent performs preliminary ordering of ink layers based on their light blocking effects before the curing process. By pre-arranging the layer sequence with inks of large light blocking effect in deeper positions and inks of small light blocking effect in top positions, the system ensures optimal light penetration paths are established in advance, maximizing curing efficiency.

Inventive Principle:

Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This configuration enhances the film strength of the layered ink by ensuring uniform light penetration and curing, improving the overall quality of the printed image.

Implementation Method 1

an irradiation device that applies light to the photocurable color inks that have been jetted onto the recording medium

Methodology Applied

Scientific EffectPhotocuring: Photopolymerisation

Implementation Method 2

the ink layer having the large light blocking effect is positioned on the top layer side of the layered ink

Methodology Applied

Scientific EffectLight absorption: Absorption (EM radiation)

Data Source

PatentUS8807735B2Inkjet recording apparatus and inkjet recording method

Publication Date: 2014.08.19 FUJIFILM CORP

AI summary

There is provided an inkjet recording apparatus including: plural jetting heads that jet respectively different types of photocurable color inks onto a conveyed recording medium and which, when layer-jetting the different types of photocurable color inks onto the recording medium, first jet the photocurable color ink having the largest light blocking effect among the plural photocurable color inks that the plural jetting heads layer-jet; and an irradiation device that applies light to the photocurable color inks that have been jetted onto the recording medium.